
class Factory {
	   public static MusicBox getInstance (String className){
		    MusicBox  f = null ;
	          if("PianoBox".equals(className)){   
                  f = new PianoBox() ;    
	          } 
	          if("ViolinBox".equals(className)){ 
	        	  f = new ViolinBox() ; 
	          } 
	          return f ; 
	   		} 	
	   
	   }

